Researches in evolutionary biology show plenty of determining features that differentiate the humans from other primates. As it turns out, a big group of them are related to our distinctive eating habits. Thereby, you can read a lot about this theory with respect to physical fitness, weight loss or the treatment of metabolic disorders. However, looking at our nutritional evolution, it is the brain that has been impacted most significantly. Looking back to the prehistoric times, our brain was three times smaller. What was the main reason behind this remarkable growth? Yes exactly, the changes in our ancestors’ diet.
Major dietary changes = Dramatic brain growth
Of course this growth didn’t happen in a couple of days. Actually, it took over some seven million years. During this period of time, longer subtle increases and much more noticeable growth spurs alternated each other. The more significant development stages seem to show a correlation with the biggest changes in our eating habits. (1)
In the beginning of our history, there wasn’t much difference between the brain size of the humans and apes. For instance, a group of our ancestors, called Australopithecines had only about 400-500 cc brains. This remained almost completely unchanged for millions of years. After that, the Homo erectus appeared, they learnt to cook, and they had remarkable 1000 cc brains. Finally, the last significant growth happened with the debut of the Homo sapiens and their relatives the Neanderthals. Actually, this size was close to our modern day brains, about 1300-1500 cc. In conclusion, our species went through an extremely big brain expansion, which required more calories and nutrients. (2) (3)
Despite the huge time and resource investment, obtaining more fats and energy became crucial to our ancestors. Scientific researches suggest a direct relationship between the consumption of quality nutrition and the size of the brain. That being the case, even smaller deficit of certain foods could result in lower chances of survival. (4)
Meat didn’t do the trick
The diet of early humans consisted of fruits, grasses, seeds, roots, tubers, bulbs and tree bark. As a result, obesity wasn’t a big threat, however they needed significantly more calories to support brain growth. (5)
In order to solve that issue, it might sound logical that our ancestors supplemented their diets with high-calorie meats. However, they had relatively small bodies and they were not that physically gifted to easily chase big animals. Meat was a valuable food for sure, but it wasn’t a common one. That being the case, it wasn’t a major component in the growing brain project. So if it wasn’t meat than what did the trick?
It was non other than something that we consider as one of the best brain foods in our modern days as well: Fish. Fossil and paleo-environmental evidences suggest that early humans mainly lived next to lakes and rivers. This makes perfect sense, since drinking water is probably the most determining resource of the human body. In addition, animals also live in water, so it provided them with food as well. They could easily catch fishes and shellfishes, which are excellent sources of the brain-cell-building Omega-3 fatty acids. Furthermore, they could also provide them with protein, vitamins and minerals, which are crucial for proper brain function. (6)
Beside fish, these habitats usually also offered a big supply of fruits and vegetables, that increased even more the vitamin and mineral intake. Finally, bird eggs were also available seasonally that contain a wide variety of invaluable nutrients, including the memory-boosting choline.
Another milestone: The use of fire
According to researches, the development of habitual cooking could be the reason behind the latest major brain growth spur. Heated and pounded food made the digestion and absorption of nutrients more effective. In other words, our ancestors could consume these soft, energy-rich foods faster and easier, so that obtaining more calories and energy became less challenging. Since the growing brain had become continuously hungrier and hungrier it was obviously a huge advantage. (7)
In addition to satisfying the more demanding nutritional needs of the brain, cooked food also helped reshaping the human body. Those big teeth and jaws to break down all those raw foods were not necessary anymore. Furthermore, at this point bigger gastrointestinal organs were not vital either, due to the easier absorption of nutrients. Why is that important from a brain perspective? Because as teeth, jaws and guts got smaller, the heads got bigger. Consequently, this was also a big support for the growing brain. (8)
Hunting/Fishing vs Gathering
Since the regular consumption of fish played an important role in the brain growth journey, it might sound logical that the latter activity was more decisive in this process. However, the vast majority of energy-dense food still came from gathering. Consequently, vegetables, fruits, nuts and seeds were the backbone of our ancestor’s diet. All of these foods were important sources of protein, fats, vitamins and minerals that are all invaluable nutrients for the brain. (9)
Moreover, despite some of the modern paleo diets claim that the early humans didn’t consume grains at all, scientific studies suggest the opposite. Research teams have documented how wild wheat and oats were important components in the everyday menu of our ancestors. The complex carbohydrate content of these foods helped to fuel the increasingly bigger energy need of the growing brain. (10)
Gathering was generally a more important source of supply, but during seasonal hardships it became even more crucial. As I’ve already mentioned, the process of obtaining meet was more challenging and time consuming. In addition to that, sometimes meat was very scarce as well. During these times plants, nuts, seeds and wild grains were the only choices.
As you can see, solid scientific evidence suggests a direct relationship between nutrition and the development of the human brain.
However, when we compare the regular modern day diet with our ancestors’ most common food sources, the difference is huge and not necessarily for the better. Since the agricultural and industrial revolution starvation hasn’t been such a critical problem as it used to be, but a lot of people’s diet lack almost completely several invaluable nutrients for their brain and for their general health.
Do you consume enough vegetables, fruits, nuts, seeds, oats and fish? If so, are they in their natural state or rather some kind of chemically processed version?